Display device including pad arranged in peripheral area

Abstract

A display device includes a substrate including a display area and a peripheral area outside the display area, a thin-film transistor arranged in the display area, a display element arranged in the display area, an interlayer insulating layer covering the thin-film transistor, a conductive layer arranged above the interlayer insulating layer, a first insulating layer covering the conductive layer, a pad arranged in the peripheral area, and a second conductive layer covering a central portion of the pad. The pad is connected to a connection line through a contact hole, and the connection line is arranged on a same first layer as a gate electrode of the thin-film transistor. A side surface of the pad is covered by the first insulating layer or the second conductive layer.

What is claimed is: 
     
       1. A display device, comprising:
 a substrate comprising a display area and a peripheral area outside the display area; 
 a thin-film transistor arranged in the display area; 
 a display element arranged in the display area; 
 an interlayer insulating layer covering the thin-film transistor; 
 a conductive layer arranged above the interlayer insulating layer; 
 a first insulating layer covering the conductive layer; 
 a pad arranged in the peripheral area; and 
 a second conductive layer covering a central portion of the pad, 
 wherein the pad is connected to a connection line through a contact hole, and the connection line is arranged on a same first layer as a gate electrode of the thin-film transistor, and 
 a side surface of the pad is covered by the first insulating layer or the second conductive layer. 
 
     
     
       2. The display device of  claim 1 , wherein
 the pad comprises a first pad layer on a same second layer as a source electrode of the thin-film transistor, and a second pad layer on a same third layer as the conductive layer, 
 the first insulating layer includes inorganic material, the first insulating layer has an opening hole exposing a central portion of the second pad layer, and 
 the second conductive layer is in contact with the second pad layer through the opening hole of the first insulating layer. 
 
     
     
       3. The display device of  claim 1 , wherein
 the second conductive layer comprises titanium (Ti). 
 
     
     
       4. The display device of  claim 1 , wherein
 the pad comprises a metal having higher electrical conductivity than that of the second conductive layer. 
 
     
     
       5. The display device of  claim 1 , further comprising:
 a connection electrode connecting a drain electrode of the thin-film transistor to a pixel electrode of the display element, 
 wherein the connection electrode comprises a same material as the second conductive layer. 
 
     
     
       6. The display device of  claim 1 , wherein
 the pad comprises a first pad layer on a same second layer as a source electrode of the thin-film transistor, 
 the first insulating layer and the interlayer insulating layer comprise opening holes corresponding to a central portion of the first pad layer, and 
 the second conductive layer is in contact with the first pad layer through the opening holes of the first insulating layer and the interlayer insulating layer. 
 
     
     
       7. The display device of  claim 1 , wherein
 the pad comprises a first pad layer on a same second layer as a source electrode of the thin-film transistor, 
 the second conductive layer is arranged on the first pad layer, and 
 the first insulating layer and the interlayer insulating layer cover side surfaces of the second conductive layer and the first pad layer. 
 
     
     
       8. A display device, comprising:
 a substrate comprising a display area and a peripheral area outside the display area;
 a thin-film transistor arranged in the display area; 
 a display element arranged in the display area; 
 a pad arranged in the peripheral area; and 
 a second conductive layer covering a side surface and an upper surface of the pad, 
 wherein the pad is connected to a connection line through a contact hole, and the connection line is arranged on a same first layer as a gate electrode of the thin-film transistor. 
 
 
     
     
       9. The display device of  claim 8 , wherein
 the second conductive layer comprises titanium (Ti). 
 
     
     
       10. The display device of  claim 8 , further comprising:
 a storage capacitor arranged in the display area, 
 wherein a first electrode of the storage capacitor is arranged on the same first layer as the gate electrode of the thin-film transistor, and a second electrode of the storage capacitor is arranged on a same second layer as a source electrode of the thin-film transistor. 
 
     
     
       11. The display device of  claim 8 , further comprising:
 a conductive layer arranged above the thin-film transistor, 
 wherein a first pad layer on a same second layer as a source electrode of the thin-film transistor, and a second pad layer on a same third layer as the conductive layer, are stacked in the pad. 
 
     
     
       12. A display device, comprising:
 a lower substrate comprising a display area and a peripheral area outside the display area; 
 a plurality of pixels arranged in the display area, each comprising a thin-film transistor and an organic light-emitting diode; 
 a thin-film encapsulation layer covering the organic light-emitting diodes, and comprising at least one inorganic encapsulation layer and at least one organic encapsulation layer; 
 an upper substrate arranged above the thin-film encapsulation layer and facing the lower substrate; 
 a pad arranged in the peripheral area; 
 a second conductive layer covering a central portion of the pad, 
 wherein a side surface of the pad is covered by the second conductive layer or a first insulating layer; and 
 a plurality of color converting layers arranged on the upper substrate and corresponding to at least a portion of the plurality of pixels, and comprising a plurality of quantum dots. 
 
     
     
       13. The display device of  claim 12 , wherein
 the pad is connected to a connection line through a contact hole, and the connection line is arranged on a same layer as gate electrodes of the thin-film transistors. 
 
     
     
       14. The display device of  claim 12 , wherein
 the second conductive layer comprises titanium (Ti). 
 
     
     
       15. The display device of  claim 12 , further comprising:
 a connection electrode connecting the thin-film transistor and a pixel electrode of the organic light-emitting diode in each of the pixels, 
 wherein the connection electrode comprises a same material as the second conductive layer. 
 
     
     
       16. The display device of  claim 12 , wherein
 the plurality of pixels comprises a first pixel, a second pixel, and a third pixel, 
 one of the color converting layers corresponding to the first pixel emits a red light, 
 one of the color converting layers corresponding to the second pixel emits a green light, and 
 none of the color converting layers are arranged in correspondence with the third pixel. 
 
     
     
       17. The display device of  claim 12 , further comprising:
 a plurality of color filters arranged on the upper substrate and corresponding to the plurality of pixels. 
 
     
     
       18. The display device of  claim 12 , wherein
 the organic light-emitting diodes comprised in the plurality of pixels emit a blue light. 
 
     
     
       19. A display device, comprising:
 a lower substrate comprising a display area and a peripheral area outside the display area; 
 a plurality of pixels arranged in the display area, each comprising a thin-film transistor and an organic light-emitting diode; 
 a thin-film encapsulation layer covering the organic light-emitting diodes, and comprising at least one inorganic encapsulation layer and at least one organic encapsulation layer; 
 an upper substrate arranged above the thin-film encapsulation layer and facing the lower substrate; 
 a pad arranged in the peripheral area; 
 a second conductive layer covering a central portion of the pad, 
 wherein a side surface of the pad is covered by the second conductive layer or a first insulating layer; and 
 a conductive layer arranged on the thin-film transistors and connected to the thin-film transistors through contact holes.